The subject of the present invention is a caliper body for a fixed caliper disk brake, usable in vehicles and intended, in particular, for high-performance motor cars.
A further subject of the present invention is a disk brake unit having a caliper body of the type specified above.
It is known that a caliper body for a fixed-caliper disk brake can be associated with a disk in a manner such that its distance from the disk is kept unchanged. As is well known, the caliper body comprises a first half-body which can house first means for generating a braking force and which is arranged facing a first braking surface of an outer side of the disk, as well as a second half-body, which can house second means for generating the braking force and which is arranged facing a second braking surface of an inner side of the disk. The first and second half-bodies are connected, by fixing means, to two bridge elements arranged astride the disk.
The term “outer side” is intended to define the side of the disk brake unit which faces outwardly relative to the vehicle when it is mounted on the hub and on the stub-axle or hub-carrier of the wheel. Similarly, the term “inner side” is intended to define the side of the unit which faces inwardly relative to the vehicle when mounted on the wheel hub.
Moreover, reference will also be made below to an “axial axis” (indicated “a” in FIG. 1), a “radial axis” (indicated “r” in FIG. 1), and a “tangential axis” (indicated “t” in FIG. 1), which are intended to define a first axis parallel to the axis of rotation of the disk, a second axis perpendicular to the axis of rotation of the disk and extending through the axis of rotation, as well as a third axis parallel to the plane of rotation of the disk and perpendicular to the other two axes, respectively.
As is known, during the braking of a vehicle, the significant and large forces which affect the caliper body are a clamping force and a braking force. These forces are produced by the means for generating the braking force, for example, by at least one pair of cylinder and piston units which are housed in the half-bodies and the pistons of which act on the opposed braking surfaces of the disk by means of pads.
The force of the clamping of the pads against the braking surfaces of the disk is directed axially and is balanced by the structure of the caliper body which is disposed astride the disk. In particular, this force is opposed by the bridge elements which extend around the disk, forming closed force rings. This force stresses the caliper body, causing an opening-out of the bridge elements or, in other words, a bending of the caliper body about tangential axes.
The braking force, on the other hand, is directed tangentially and, in particular, in the direction of rotation of the disk. This force is transmitted by the disk to the pads and is opposed by shoulders in the bridge elements, so as to be discharged onto support means of the caliper body which are fixed, for example, to a stub axle or hub-carrier of a wheel of the vehicle. This force stresses the bridge elements, also deforming portions of these elements which are necessary for the connection of the half-bodies. The braking force is also discharged onto the support means, purely on the side of the caliper body which faces the inner side of the disk, also causing the caliper body to bend about radial axes.
As is well known, the above-mentioned forces are distributed non-uniformly on the caliper body and, moreover, their magnitude is variable over time so that, in addition to deformations of the caliper body which are sometimes not acceptable for correct operation of the disk brake, they also cause vibrations and undesired whistling.